Darkshot

iTrader: (4)

I am having trouble getting my engine to stay running at idle. The engine will also die when I push in the clutch while driving and take my foot off the gas. I'm wondering if I'm asking my 65# injectors to squirt too little fuel. sPW is about 1.3ms and DC is 3% when trying to idle. Sometimes it idles just fine for several minutes then just stop running with no warning or sputtering. Navigating parking lots is a nightmare, I'm restarting it 4-5 times just trying to find a parking spot.

Darkshot

iTrader: (4)

Attached are some short datalogs of the stalling in both closed loop and open loop. Sometimes it happens when just idling untouched, others I rev'd it and it stalled as the revs fell back down. In DL 5_steering I was messing with the steering wheel and it would stall every time I turned the wheel (engine load). Other times (not captured in logs) it will die when the radiator fan kicks on (also load, but damn so minor!). It definitely seems to be sensitive to load but not all the time.

About 1 in 10 times the stall saver will catch it and the RPMs will surge without stalling.

I'm running a basically factory caprice bin (EBL_F_2018) with one minor VE learn done and Open Loop Decel disabled (had lots of trouble backfiring through exhaust with OpLpDecel).

I have my idle at 750 RPM, 550 was too low and it was constantly stalling which was odd to me, LO5 crate motor original cam.

Remove the .txt to view the logs in EBL WU.

RBob

iTrader: (1)

I don't see anything in the log files that points to the tune. For a stock L05 that engine should idle glass smooth at 550 RPM.

There is likely a mechanical issue at fault here. As when it stalls, it just dies, and quickly at that. I'd do the easy to check stuff first, such as looking at the plugs, compression check, firing order and so on.

RBob.

Darkshot

iTrader: (4)

Something just clicked for me regarding my idle.

My car was formerly an automatic. When I converted it I permanently connected my P/N switch and never installed the clutch safety switch so I could start it without pressing the clutch. Is the EBL running differently and causing problems thinking that I'm in Park all the time driving around?

RBob

iTrader: (1)

If the P/N input to the ECM is grounded, yes, the ECM thinks it is in P/N. Leave that input to the ECM open (pin B10) when using a stick shift.

RBob.

Darkshot

iTrader: (4)

Is that the same as the clutch safety circuit? My understanding was that this would prevent me from starting the car.

Or are you just telling me to hook the safety switch up properly?

RBob

iTrader: (1)

> Is there a minimum recommended aPW/sPW and duty cycle?

I never answered the original question. There is no lower limit to the injector DC%. It is just a calculated value.

As for minimum sPW & aPW, this gets tricky. There are minimums in the calibration. The one(s) for sPW cause the ECM to switch to async mode once below the minimum.

Then for async mode there is both a minimum and a maximum. The max is needed to ensure enough time for the injector to open then close before the next event (every 12.5 milli-seconds).

Any amount over the max is saved for the next firing event.

When under the min the PWs are accumulated until over the minimum, then fired.

For the switching between sync and async mode to work the injector compensations have to be dead on. Which isn't always easy. In this case prevent async mode by setting the two values in this table to 0:

INJ - ASync Transition PW - TBI Only

RBob.

Darkshot

iTrader: (4)

Cancel this...I forgot that the wires that should go to the clutch safety switch and the P/N ECM signal wires were separate.

That swap was 7 years ago now.

Darkshot

iTrader: (4)

Update: It idles at 550 with the EST disconnected. I've tried everything else. I'm going to start looking into the timing.

With the EST disconnected the sPW goes up to 2.0 ms (at 550 RPM) from the usual 1.3 ms (at 750 RPM). Is there any chance this is what's keeping it running?

RBob

iTrader: (1)

Hook up the timing light and verify that with the EST/BYPASS open the base timing is 0* BTDC. Do a key-off and reconnect the EST/BYPASS connector. Restart the engine and check the timing again. The mark on the damper should move toward the passenger side of the car.

If it does not and moves toward the drivers side of the car, the pickup coil wires to the ICM are backwards.

RBob.

Darkshot

iTrader: (4)

Update:

With EST connected, computer wants to give the engine about 20 degrees timing (bounces between 17 and 22 in reality). Confirmed via timing light. It does not idle in this state.

So I disconnected the EST and gave the engine its desired 20 degrees manually via the distributor. Confirmed via timing light. IT RUNS AT 550 in this state! It runs pretty well too but does surge occasionally. Doesn't stall though.

I put the base timing back at 0, reconnect EST, won't run at all.

I honestly don't know what's different between these two configurations. It's getting ~20 degrees in both situations confirmed by timing light but runs without EST and doesn't run with EST. The timing does fluctuate with EST like I said..... I assumed that was normal. Idle State SA is enabled and set at 20 degrees.

I have installed a new ACDelco pickup coil and have tried multiple ignition control modules and have the same problem on all.

What else is there? Do I need to start looking for broken wires in the body harness?

Sorry I know this isn't exactly the right forum, just continuing the thread.

RBob

iTrader: (1)

I'm not sure what is going on, but make this change and flash it in. Zero out both SA idle compensation tables:

SA - Idle Low Compensation
SA - Idle High Compensation

That will prevent the SA from moving around at idle.

Since you've had the EBL Flash for some years now, when did this no-idle issue start?

RBob.

Darkshot

iTrader: (4)

Stopped SA from fluctuation, but no effect on running.

My answer to this isn't very satisfying. For the past 5 years the car has seen little use, probably about 2000 miles total. I was in college and it's kind of a blur how the car was performing. I seem to remember having the issue throughout this time although I had my idle jacked up. The last time I tuned it before now was about 2010 from what I can remember and it must have been doing it then because I had my idle set high. I also seem to remember it getting worse throughout college. 2009 was the auto to manual swap, and I simply cannot remember if I was having trouble with the auto or even before I bought my first EBL in 2006.

I'm rambling now but it's entirely possible that this problem has existed since I've owned the car, but it's also possible that it developed over the last 5 years while I was in college.

Unfortunately I can't tie it to a specific event.

My next action is to rebuild the TBI with new gaskets and try running it with all vacuum ports sealed off just to be sure.

The previous owner swapped in the engine. It's definitely an L05 crate motor (block casting, 193 heads, roller equipped) and I have every reason to believe it's the stock cam but I guess I can check with him.

FYI I've had EBL flash for a couple weeks, EBL classic for 10 years before that.

RBob

iTrader: (1)

Understand about not knowing when it occurred. In many ways it doesn't make sense that opening the EST/BYPASS and setting the base to 20* BTDC it idles OK. But doesn't idle when the ECM sets the timing to 20* BTDC.

The only difference is that with the EST/BYPASS open the ICM is controlling the dwell and firing point.

While with the EST/BYPASS closed the ECM is controlling dwell and the firing point.

But then again, there may be no difference regarding the firing of the spark plugs. But there is going to be a big difference in the coil dwell. With the ECM controlling it, the dwell is going to be shorter.

So, good possibility that the coil is bad. The other item to check is the two wire pigtail between the coil & distributor. Wiggle it with the engine running, see if that makes it cut out.

Hopefully this is a GM distributor, ICM, and ignition coil. If not that should be corrected.

Having resistor spark plugs properly gapped should also be checked.

RBob.

Darkshot

iTrader: (4)

No dice on the coil. Just replaced it with a brand new ACDelco unit, no change.

Brand new ACDelco plugs gapped myself to 0.035. Ran the same with the old plugs, which were about 8 years old and came out all looking great and similar.

Darkshot

iTrader: (4)

Disconnecting EST throws (obviously) a SES light. Are there any changes the computer makes to the fueling, or anything else in the way the engine is managed, while there is an active SES light? Some kind of semi-safe mode in the hard code or something? Other than the lack of ECM controlled timing, of course.

RBob

iTrader: (1)

Not for a code 42. The ECM even goes through the SA calculation and programs the hardware for it. But since the ECM has also opened the EST/BYPASS the distributor ignores it.

I do have a thought, remove the CALPAK chip from the ECM and see if that changes things. If it does look at the chip pins and check for any solder shorts. If so remove the short and reinstall the CALPAK.

RBob.

Darkshot

iTrader: (4)

I tried removing the CALPAK. SES light (CALPAK) of course.

At first the engine wouldn't start at all. Then it would start and sputter along at like 200 RPM for a bit and eventually die. I had my hood open and air cleaner off, it was interesting hearing/seeing the injectors fire so slowly.

After restarting it and giving it some throttle revs it started running as before...will idle at 750, barely at 700, not at 650, 600, 550, or anything else.

I have my flash banks set up such that I can go 0, 1, 2, 3, 4 and the only change is the idle speed: 750, 700, 650, 600, 550. Helpful in troubleshooting.

I'm going to try and get my hands on entirely different distributor and see what happens, I think a buddy might have some spares.

Also, I was messing around for about 20 minutes before pulling my EBL out of the dash. When I did it was very hot. Almost too hot to handle. I seem to remember this being normal though, can you confirm?

RBob

iTrader: (1)

OK, so no difference. Was a long shot but worth trying.

Good idea.

I don't believe that it should be that hot. They run warm but shouldn't too hot to handle. There might be a shorted solenoid, IAC, or relay coil. Will need to measure the resistance of these devices. Needs to be above 22 ohms to be good.

RBob.

Darkshot

iTrader: (4)

Could the VSS have anything to do with this? Was trying to drive today and the car was acting extra weird and threw a VSS code, my speedometer was also bouncing around funny.

Darkshot

iTrader: (4)

Problem fixed.

Buddy had an HEI distributor sitting around he let me borrow.

The first thing I noticed was on the 8 point reluctor wheel, the tips of the star on the good distributor were very close, even slightly touching the 4 contacts they rotate inside of.

On the distributor I pulled out of my engine the contacts were as much as 1/8" away from the tips of the reluctor. Appears to be a combination of the reluctor tips wearing down and the contacts getting pushed away or damaged.

Thank you for all your help on this.

RBob

iTrader: (1)

That's good news on an early Sunday morning.

Have to wonder what happened to cause that. Maybe rusted away, I've seen well used distributors that had a lot of rust in them.

RBob.

Darkshot

iTrader: (4)

I have to assume this is the original distributor to the car, which just turned 197K miles. There was indeed a lot of rust in there. I brushed it all off with a wire brush (by hand, not a wheel) when I changed the pickup coil but compared to the replacement one that wheel was cashed.

The car drives great now and doesn't stall, but there are still some idle issues that I believe are in fact related to the tune. These existed before and my plan was always to revisit them after college, but the deteriorating distributor over the past couple years combined with hardly driving the car really muddied the waters and is the reason why I couldn't pinpoint when the problem started.

RBob I know you are a proponent of using strictly GM distributors. Do you have any experience with the ACDelco remans sold by Rock Auto for $230? Or is there a way to get a new one?